From a2bf964f30894457a4eaffe0287f70ae98910bcb Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Sat, 11 May 2013 11:11:40 -0700
Subject: [PATCH] packer/rpc: Properly support hooks

---
 builder/amazonebs/builder.go | 3 +++
 builder/amazonebs/hook.go    | 4 ++++
 config.go                    | 5 +++++
 packer.go                    | 1 +
 packer/rpc/environment.go    | 9 ++++-----
 5 files changed, 17 insertions(+), 5 deletions(-)
 create mode 100644 builder/amazonebs/hook.go

diff --git a/builder/amazonebs/builder.go b/builder/amazonebs/builder.go
index 7305dfe84..ea62703e6 100644
--- a/builder/amazonebs/builder.go
+++ b/builder/amazonebs/builder.go
@@ -60,6 +60,9 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook) {
 		MaxCount:     0,
 	}
 
+	hook.Run(HookPreLaunch, nil, ui)
+	return
+
 	ui.Say("Launching a source AWS instance...\n")
 	runResp, err := ec2conn.RunInstances(runOpts)
 	if err != nil {
diff --git a/builder/amazonebs/hook.go b/builder/amazonebs/hook.go
new file mode 100644
index 000000000..5e3d2a2b8
--- /dev/null
+++ b/builder/amazonebs/hook.go
@@ -0,0 +1,4 @@
+package amazonebs
+
+// This hook is fired prior to launching the EC2 instance.
+const HookPreLaunch = "amazonebs_pre_launch"
diff --git a/config.go b/config.go
index 494686202..903ee6638 100644
--- a/config.go
+++ b/config.go
@@ -90,3 +90,8 @@ func (c *config) LoadCommand(name string) (packer.Command, error) {
 
 	return plugin.Command(exec.Command(commandBin))
 }
+
+func (c *config) LoadHook(name string) (packer.Hook, error) {
+	log.Printf("Loading hook: %s\n", name)
+	return plugin.Hook(exec.Command(name))
+}
diff --git a/packer.go b/packer.go
index 7237c4e14..40c4aa0eb 100644
--- a/packer.go
+++ b/packer.go
@@ -87,6 +87,7 @@ func main() {
 	envConfig.Commands = config.CommandNames()
 	envConfig.Components.Builder = config.LoadBuilder
 	envConfig.Components.Command = config.LoadCommand
+	envConfig.Components.Hook = config.LoadHook
 
 	env, err := packer.NewEnvironment(envConfig)
 	if err != nil {
diff --git a/packer/rpc/environment.go b/packer/rpc/environment.go
index 302c716d2..03a020570 100644
--- a/packer/rpc/environment.go
+++ b/packer/rpc/environment.go
@@ -50,13 +50,12 @@ func (e *Environment) Hook(name string) (h packer.Hook, err error) {
 		return
 	}
 
-	_, err = rpc.Dial("tcp", reply)
+	client, err := rpc.Dial("tcp", reply)
 	if err != nil {
 		return
 	}
 
-	// TODO: Hook
-	h = nil
+	h = Hook(client)
 	return
 }
 
@@ -89,14 +88,14 @@ func (e *EnvironmentServer) Cli(args *EnvironmentCliArgs, reply *int) (err error
 }
 
 func (e *EnvironmentServer) Hook(name *string, reply *string) error {
-	_, err := e.env.Hook(*name)
+	hook, err := e.env.Hook(*name)
 	if err != nil {
 		return err
 	}
 
 	// Wrap it
-	// TODO: Register hook
 	server := rpc.NewServer()
+	RegisterHook(server, hook)
 
 	*reply = serveSingleConn(server)
 	return nil